Fluid irradiator



Jame 2?, 393%. M. J. QQRQAs ET AL FLUID IRRADIATOR Filed April 2, 1935 2Sheets-Sheet l INVENTORS MERRILL I DOR'CAS I GEORGE CSUPPLEE BY FRANKREMESCI'LJ'K ATTORNEY Patented June 27, 19 39 FLUID IRRADEATORApplication April 2, 1935, Seriai No. 14,206

15 Claims.

This invention relates to apparatus for the irradiation of liquids withradiant energy and more especially to the radiation of liquid foodstuffs, such for example as milk, with ultra-violet energy whereby anincrease in vitamin content is secured. The radiation of such substancesas milk with ultra-violet energy produces What is known as anti-rachiticactivation and this activation is generally attributed to an increase inthe vitamin content. However, the particular wave length of energyemployed and the particular type or" activation secured forms no part ofthe present invention since the apparatus may be employed with liquidsof any type and with energy from any source.

An object of our invention is to devise an improved apparatus for theirradiation of liquids. Another object of our invention is to secure aneven distribution of the film of liquid over the supporting surfaceduring irradiation. A still further object of our invention is toprovide an irradiator whereby separate bodies of liquids may beirradiated at the same time under the same conditions of irradiationfrom a source of ultraviolet energy. A still further object of ourinvention is to provide means for maintaining the liquid film supportingsurfaces exactly vertical and also to provide means for maintaining thefeeding slot on a curved surface exactly horizontal. Another object ofour invention is to provide an apparatus in which all parts in contactwith the liquid being irradiated are removable as a unit for cleaning.

These and other objects of our invention will in part be evident andwill in part be set forth in the following specification, havingreference to the accompanying drawings, in which:

Fig. l is a top view of an irradiator illustrating one embodiment of ourinvention.

Fig. 2 is a cross section of the film supporting shell taken on line 22of Fig. 1.

Fig. 3 is a diagrammatic view showing the method of laying out the shapeof said shell.

Fig. i is a vertical section taken on the line i-Q- of Fig. 1.

Figs. 5, 6 and 7 are detailed cross sections taken on the lines 5-5, 65, and 'il of Fig. 4 showing means for adjusting the position of theshell supporting the liquid film during irradiation.

It is now well known that irradiation of such liquid food stuffs as milkwith various types of energy is desirable for the purpose ofantirachitic activation, sterilization, etc. The irradiation of milkwith ultra-violet energy to produce anti-rachitic activation is becomingof increasing commercial importance. Heretofore, the apparatus has beenof relatively large size or of very small laboratory size. Wehavedevised an apparatus which is particularly adaptable for use in smallcommercial installations or in large scale laboratory investigations,but it may also be used in larger installations.

It is well known that the laboratory investigations of the degree ofactivation of various liquids, such as whole milk, skim milk, whey, orconcentrated milk, are tedious and diiiicult. One of the reasons whysuch evaluations of antirachitie potency are difiicult is that thetesting of such products must be carried out by biological assays. Incomparing the potency of various fluids it is essential that the fluidsbe irradiated under exactly the same conditions. This is not easy forvarious reasons. One of these is the fact that some sources ofultra-violet energy do not emit such energy at an absolutely constantrate. Hence, it is desirable that the samples to be compared beirradiated simultaneously from the same source of energy. We havedevised an apparatus which permits of such irradiation.

In any irradiation of food products, and especially of dairy products,it is necessary that the devices used in treating them be cleanedfrequently. It is well known that such products are subject to spoilagedue to scouring, etc. This is due to the presence of bacteria. For thisreason, among others, the apparatus must be thoroughly cleanedfrequently. We have devised an apparatus in which the parts contactingwith the irradiated liquid can be readily removed for frequentcleanings. Moreover all parts in contact with milk are removed as a unitand may be taken to a trough or the like for cleaning. This is an addedconvenience and reduces the danger of water coming in contact with themechanism for producing ultra-violet energy.

In any demountable apparatus the parts are subject to slight variationsin position upon reassembly. In a device of the type which we haveinvented it is important that the parts be capable of adjustment uponassembly in order that they may be in correct position. In maintaining athin film of liquid to be irradiated, such as a film of milk having athickness of from .15 to .35 mm., ii the milk distributing means is notlevel considerable variations in the thickness of the film may result.For this reason we have provided our device with means for adjusting theposition of both the milk trough and the irradiating screen afterassembly.

In the embodiment of our i vention illustrated in the accompanyingdrawings we have shown an arc lamp as the source of energy. While wehave found an arc lamp using carbon electrodes with suitable flamematerials in the core to be the best source of irradiation, ourinvention is not limited to such a source. In the drawings, there isshown an arc lamp A having electrodes E and driven by suitableconventional apparatus contained in a housing H. The housing is securedto a frame work F which is formed in. any suitable manner, as bysubstantially vertical angle member In and substantially horizontalangle members H. The frame work may rest on any surface, such as thefloor of the room in which the irradiation is being carried out. Inorder that it may be secured thereto, if desired, suitable members l2are provided at the foot of the vertical member H3. The vertical membersEB are preferably arranged at the corners of a rectangle. The are lampwith its housing H is mounted at one of the shorter sides of therectangle. Opposite to the arc lamp housing there is provided a platel4, since we prefer not to utilize this side of the device forirradiation purposes. However, it is within the scope of our inventionto arrange the vertical members it at the corners of a square, pentagon,hexagon, etc. in which case three, four, five or more irradiating shellsor screens would be provided instead of the two shown in Fig. 1.

On the two longer sides of the rectangle are arranged irradiating shellsor screens. -A cross section through one of the shells in shown in Fi 2.The shell consists of a ver ical film supporting surface it, an uppertrough ii and a lower receiving trough H8. The film supporting surfaceis curved as is shown in Fig. 3 and as will be described more in detailhereinafter. The upper and lower troughs H and i8 conform to thecurvature of the milk supporting surface. The lower trough i8 isprovided with an outlet la.

The upper trough ll is divided into two portions 22, 2% by a verticalpartition or baffle 22! which is substantially parallel with thefilm-supporting surface 13. The outer portion 22 is provided with aninlet The inner pormion 2:9. is provided with a slit 25 extendingthrough the film supporting surface iii. The purpose of this slit is tosupply milk. evenly to the film supporting surface 55. It has been foundthat the supplying of milk to a surface at a constant head and through aslit is an efficient means for se-- curing a film of a given uniformthlcrrness. The baflle 2! to prevent irregularities, such as swirls oreddies, in the flow in the trough of the fluid being irradiated frominterfering with the even flow of the fluid through the slit. To effectthis result it is not absolutely necessary that the balile extendentirely to the bottom of the trough.

In the operation of the device the liquid to be irradiated, as forexample milk, enters the outer portion 22 of the trough ii through theinlet The milk is evenly di tributed in the outer portion of the troughand flows over the baiile it into the inner portion 1t hen flowsoutwardly through the slit 25 and down the film supporting surface Itand is collected in. the trough Hi from whence it is removed through theoutlet Hi. In ordinary operations under commercial conditions the two iiets of the separate troughs would be connected and the outlets of thelower troughs of the separate shells would be connected. However in caseit is desired to conduct comparison tests on different liquids, oneliquid would be introduced into the trough of one shell and the otherliquid would be intro 3d into the trough of the other shell. In this theirradiated liquids would of course be kept separate. By this means it ispossible to ir adiate different liquids under absolutely tr e 1 ditionsfor the purposes of comparison.

As shown above, the provision of two or more shells. is of considerableadvantage in. case the irradiator is used in the laboratory. The sameconstruction gives manifold advantages in cornmercial installations. Theshells constituting the irradiating surface and the troughs can be removed for cleaning or other purposes. This is of especial importance incase the apparatus is used for irradiating milk. It is well known thatextreme cleanliness is required in all dairy operations, sinceundesirable flavor and odor changes would soon occur if bacteria weregiven an o portunity to develop. The simple provisions for thedisassembly of the device is of marked importance in commercial as wellas laboratory operations. Moreover, the demand for irradiated milk issubject to fluctuation. Milk is a perishable commodity and theirradiated mill; cannot be stored for long periods of time. Accordinglyit is desirable to have a device which will permit of some alteration incapacity and this without change in the operating characteristics. Byusing only one irradiating shell the capacity of the device may be cutin half and the operating conditions will be absolutely unchanged. Ofcourse in case of an irradiator having more than two screens thevariation in capacity would be even greater. In the past it beenpossible to operate known irradiators at varying capacity only bydisturbing predetermined film charactoris.

Furthermore, from a manufacturing standpoint the construction offersadvantages. In case a customer desires an irradiator of a smallercapacity than that of the standard unit it is possible to ship him anirracliator having only one shell and with a blank sheet to occupy theposition normally occupied by the other shell. The construction would bethe same throughout and in case the customer eventually desiredincreased capacity it would only be necessary to provide him with thesecond shell which could readily be placed in position upon the removalof the blank I sheet.

If still smaller units are desired for comparing the treatment ofdifferent liquids, each shell may be divided into two or more sectionsby pro-- viding baflles to separate the troughs ill and 58 into sectionsand baffles on the treating surface to prevent the liquids fromcommingling. With this arrangement and a separate means for supplyingand withdrawing liquids from the several sections, different liquids maybe irradiated at the same time on each section of the shell.

It is, of course, desirable that the milk or other liquid beingirradiated flow in a sheet of uniform thickness over the entiresupporting surface. To do this .it is necessary that the slit 25 belevel throughout its length. Since the slit does not lie in a straightline but in a curve it is necessary to level the plane containing thiscurve. Under special conditions this might be done by rotating the planein which the slit lies about a single e axis but in general it isnecessary to rotate in plane about separate axes. The most simplearrangement is, of course, have these axes at right angles to eachother. We have provided means for such adjustments and these means areshown in detail in Figs. 4, 5, 6 and 7. The vertical angle members Ii!are provided with studs 25 and 2t, arranged preferably at equal heightsas a matter of convenience. These studs consist of a threaded portion 27and an outer portion 28 which is provided with a neck 29. One of thesestuds, as for example the stud 25, has its threaded portion extendingthrough a hole 3! in one of the vertical members it! as is clearly shownin Fig. 5. The stud 26 has its threaded portion extending through a slot32 in the opposite vertical angle member as is shown in Fig. 6. Theirradiator shell is provided with vertical members 34 at the endsthereof. These vertical members 3 1 are provided with slots which are inthe shape of an inverted key hole. In assembling the irradiator shell onthe supporting frame work the head of the studs is placed at the lowerpart of the key hole shaped slots. The irradiator shell is then allowedto drop slightly so that the neck of the stud engages the upper narrowerportion of these slots. The head of the stud is of such size that itwill pass through the lower enlarged portion of the slot but will notpass through the upper narrower portion of the slot. The irradiatorshell is thus held firmly to the framework of the device. In case thetwo ends of the milk feeding slit are level, the nut on the threadedportion of the stud 26 is loosened and adjusted up or down to the extentnecessary to bring the two ends of the milk feeding slit into the samehorizontal plane.

In case portions of the slit between the ends are not in the samehorizontal plane with the ends it is necessary to make furtheradjustments. For this purpose adjusting members t! are provided at eachside as shown in Fig. '7. This adjusting member M consists of a bolt 32threaded through the angle member Itl. Suitable means 43 are providedwhereby the bolt may be readily turned thereby moving the end of thebolt 42 with respect to the angle member iii. The ends of the bolts 42engage the vertical members near the bottoms of the ends of theirradiator shell and serve to tilt the irradiator shell about an axispassing through the upper surfaces of the stud members 25 and 265. Byadjusting the bolts 32 in or out it is possible to bring any pointsintermediate the ends of the mill: feeding slit into the same horizontalplane as its ends. Since the slit lies in a plane and s nce three pointsdetermine a plane this will insure that the entire slit is level. Afterthis has been done the members 4| are locked in position h suitable locknuts 4% which are conveniently nuts as shown.

Thus it will be seen that we have provided a simple and eflicient meansfor keeping the milk feeding slit level. The milk feeding trough isposition relatively to the milk feeding sl t the top of the partition orbafl'le M is then also level. Thus we have insured that there will be aneven head of fluid throughout the circumference of the irradiator shell.This results in an even flow of milk throughout the circumference of theslit 2%. It is of course to be understood that each irradiator shell isseparately adjusted.

l iaximuin efficiencies of irradiation are secured when the sameintensity of energy is applied to each unit of surface of the film beingirradiated. This s because it has been determined that certa.intensities or periods of irradiation are most efiicient and an endeavoris made to irradiate each portion of the film as this intensity and forthis period. Irradiating a portion of the liquid for a greater periodand a portion for a shorter period thus giving the same average periodis not as satisfactory. For one thing the rate of activation decreasesrapidly after the period of maximum efliciency is passed. Hence, theover-irradiated liquid does not have an increased activation sufficientto compensate the under-irradiated liquid. Moreover, excess irradiationmay cause undesirable chan es, such as an undesirable odor or taste, ormay even result in decreased activation. Similarly applying the radiantenergy with uneven intensity upon the film surface results in decreasedeiiiciencies. Thus in order to obtain maximum efficiency it is desirableto irradiate the entire surface of the film uniformly. Where crcumstances permit, this can be done by having the milk flow over theinteior surface of a circular cylinder with the source of energy at thecenter. However, it is often inconvenient or impossible to use such asurface because of the size of th are lamp. In such cases it ispreferred to shape the surface as hereinafter described to give uniformintensity of impingement of the rays throughout a larger arc of thesurface.

It is known that the intensity of irradiation upon a surface normal tothe direction of radiation varies inversely as the square of thedistance from. the source. It is also known that when the surface isinclined the intensity of the irradiation varies as the cosine of theangle of incidence. By taking advantage of these two factors it ispossible to uniformly irradiate surfaces at varying distances from thesource of energy in the same horizontal plane. Such an effect is securedin the device disclosed in our application. In Fig. 3 We show details ofthe development of a surface for an irradiator screen designed to securean even intensity along a given horizontal cross section. Fig. 3represents diagrammatically a cross section through the center of thearc lamp and one of the irradiator shells. The point corresponds to thecenter of the energy source, i. e. the point of maximum intensity of thearc. A plurality of equal angles are laid off by lines passing throughthis point. These angles should be as small as convenient, but we havefound that angles of 5 degrees give a contour of the section of theirradiator shell which is satisfactory. A distance L is laid off betweentwo of the lines having an angle A between them. Ordinarily this wouldbe laid off from the line which is to be the center line of the surface.An arc is drawn with radius L which will intersect the next adjoiningline. Ordinarily this arc will intersect this line in two points, inwhich case the point nearest 0 is employed. The distance L should beslightly greater than the chord between two adjacent 5 degree radii.From this point, where L intersects the adjacent line, an equal distanceL is laid off intersecting the next line. This is continued around untila contour has been developed sufficiently large for the purpose desired.We have found that by using the angle as 5 degrees that good results areobtained when eight such 5 degree angles are laid off on either side ofthe center line. The points thus determined are connected by a smoothcurve and this determines the contour of the cross section of theirradiator shell.

It will be evident that in this manner the average intensity ofirradiation upon each area thus determined will be equal. Each width Lof the vertical section is the same. The amount of light radiated in apencil of rays having the same central angle A is the same. Hence equalamounts of energy are impinged upon equal areas. Dividing the equalenergies by the equal areas, it is obvious that equal intensity results.While it be true that the energy intensity on every portion of this areais not absolutely constant yet we have found that by using the angle Aequal to 5 degrees the departure of the intensity from th average is notsufhciently great to cause unfavorable irradiation conditions. In casesuch conditions were produced, we would of course make the angle Asmaller than 5 degrees. As a matter of fact the use of a smooth curveinstead of a plurality of straight lines connecting the points asdetermined as above set forth tends to make the conditions approach morenearly the theoretical shape in which absolutely even irradiatienconditions are present.

Thus it will be observed that we have secured an irradiation device inwhich we have compens-ated for the fact that, under certain conditions,it is impossible to place the source of illumination at the center of acircular cylinder, and at the same time secured even irradiation overthe surface of the fill i of liquid being irradiated. We have alsoprovided an irradiating device which has means for insuring an even flowof liquid over the irradiating screens or surfaces and which may beeasily disassembled for thorough cleaning and accurately reassembled toinsure uniform flow. We have also provided a device which is veryaccurate in comparing the effects of uniform. radiation upon samples ofdifferent materials. While we have disclosed one type of apparatussuitable for securing these and other novel features we do not wish ourinvention to be limited to this exact embodiment, as variousmodifications therein will readily occur to those skilled in the art.

We claim:

1. In a device for irradiating liquids, the combination of means havinga film supporting surface, said means being provided with a slit nearthe top thereof; a receptacle on said means on the side opposite to saidsurface and extending above and below said slit and extending at leastthe length of said slit, said receptacle being provided wtih a bafiletherein extending above and below said slit; and means for supplyingliquid to said receptacle on the side of the baffle opposite said slit.

2. A shell for a liquid irradiating device comprising means forming avertical surface provided with a horizontal slit near the top of saidsurface, a trough on the side of said means opposite said surface, saidtrough having its bottom. below and its top above said slit andextending throughout the length of said slit, a battle in said troughextending from the bottom of the trough above the top of said slit butterminating below the top of said trough, said trough being providedwith an inlet on the side of the baffle opposite said slit.

3. A liquid irradiating device comprising a source of radiant energy, asubstantially vertical curved irradiating surface, a slit in saidirradiating surface, adapted to be positioned in a substantiallyhorizontal plane, for supplying liquid thereto, and means for adjustingsaid irradiating surface to position said slit in a horizontal plane.

4. A device as defined in claim 3, including a pair of spaced pivotalmembers adapted to support said irradiating surface and means foradjusting said irradiating surface at right angles about said pivots.

5. A liquid irradiating apparatus as claimed in claim 3 including aplurality of such adjustable surfaces positioned about the source ofradiant energy.

6. A fluid irradiating apparatus comprising a source of radiant energy;at least one film-forming unit providing a surface on which a film offlowing liquid may be irradiated by said source of radiant energy, saidsurface having a slit therein adapted to be positioned in asubstantially horizontal plane for supplying liquid to be irradiated onthe surface in a thin flow of substantially uniform thickness; and meansfor supporting said film-forming unit, said supporting means comprisingat least one pivot and at least one positioning member for adjusting theunit about an axis of said pivot.

Z. A liquid irradiating apparatus comprising a source of energy, asupporting frame, and at least one film-formin unit supported by saidframe; said film-forming unit comprising means forming a surface curvedabout a substantially veraxis and adapted to receive energy from saidsource; means for distributing liquid over said surface, said meansincluding a slit adapted to be positioned substantially horizontally;and means for receiving irradiated liquid from said surface; said unitbeing bodily removable from said frame cleaning purposes; and means foradjustably holding said unit on said frame, said holding means includingmeans for adjusting the unit about axes at substantially right angles toeach other level said slit over all portions thereof.

8. A liquid irradiating apparatus comprising, in combination, a sourceof radiant energy; an adjustable member having a surface at an angle tothe horizontal for supporting a relatively wide film of liquid to beirradiated by such energy while said liquid flows downwardly over saidsurface, said member having an edge over which liquid is supplied tosaid surface, said edge extending transversely of said surface and beingsubstantially as wide as the liquid film. to be irradiated; and meansfor adjusting said member to position said edge accurately horizontallyand thereby insure a substantially uniform supply of liquid to saidsurface over said edge, and thus maintain the thickness of said filmsubstantially uniform across the entire width thereof.

9. A liquid irradiating apparatus as claimed in claim 7, in which saidsurface is curved about an axis extending in the direction of flow ofsaid film, and in which such adjusting means is operable to adjust saidmember about axes in planes substantially perpendicular to each other.

10. An irradiating apparatus including a source of radiant energy and asurface not lying wholly in a single plane, which surface is adapted toreceive liquid to be irradiated while flowing thereover, said surfacebeing provided With an edge, adapted to be positioned substantiallyhorizontaily, over which a fiow of such liquid is supplied to suchsurface, means for adjusting said surface about axes substantially atright angles to each other to control the position of said edge relativeto the horizontal.

ll. An irradiating apparatus comprising a source of radiant energy and asurface not lying wholly in a single plane, which surface is adapted toreceive liquid to be irradiated while flowing thereover; said surfacebeing provided with an edge, adapted to be positioned substantiallyhorizontally, over which a flow of such liquid is supplied to suchsurface, and means for adjusting said surface to control the position ofsaid edge relative to the horizontal; said adjusting means comprising apivotal support and means for adjusting said surface about said pivotalsupport in directions substantially at right angles to each other.

12. In an irradiating apparatus, the combina tion of a substantiallyvertical, curved surface adapted to receive liquid to be irradiatedduring flow thereover, said surface being provided near the top thereofwith a curved slit for supplying a flow of liquid thereto, said slitbeing substantially normal to the direction of said flow; with means foradjusting the position of said surface about axes at substantially rightangles to each other to level said slit over all portions thereof.

13. An irradiating apparatus comprising a source of radiant energy; asurface adapted to receive liquid to be irradiated while flowingthereover, said surface being curved about an axis parallel to thedirection of flow of such liquid and provided with a curved edge,adapted to be positioned in a substantially horizontal plane,

over which such liquid is supplied to such surface; and means forsupporting and adjusting said surface to control the position of saidedge relative to the horizontal, said means comprising a fixed pivot, anadjustable pivot, and a positioning member for adjusting said surfaceabout said pivots.

14. An apparatus as defined in claim 1 including means for adjustingsaid first-mentioned means to control the position of said slit relativeto the horizontal.

15. An apparatus for irradiating liquid as defined in claim 7 in whichthe surface is curved and the adjusting means comprises an elementserving as a pivot, and a plurality of positioning means spaced fromsaid element and from one another for adjusting said member aboutseparate axes in planes at angles to each other.

MERRILL J. DORCAS. FRANK RENEESCH, JR. GEORGE C. SUPPLEE.

CERTIFICATE OF CORRECTION. Patent No. 2,165, 575. June 27, 1959.

MERRIIL J DORCAS ET AL It is hereby certified that error appears in theprinted specification of the above mm lbered patent requiring correctionas follows: Page 1, sec-- 0nd column, line 51, for the word "scouring"read souring; page 2, first column, line 56, after the numeral "21"vinsert serves; page 5, first column, line 71+, for "as read at; pagesecond column, line 50, and page 5, second column, line 15, claims 9 and15 respectively, for the claim reference numeral "7" read 8; and thatthe said Letters Patent should be read with this correction therein thatthe same may conform to the record of the case in the Patent Office.

Signed and sealed this 19th day of September, A. D. 1959.

Henrydian A'rsdale, (Seal) Acting Commissioner of Patents.

